| /* |
| * include/linux/hrtimer.h |
| * |
| * hrtimers - High-resolution kernel timers |
| * |
| * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de> |
| * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar |
| * |
| * data type definitions, declarations, prototypes |
| * |
| * Started by: Thomas Gleixner and Ingo Molnar |
| * |
| * For licencing details see kernel-base/COPYING |
| */ |
| #ifndef _LINUX_HRTIMER_H |
| #define _LINUX_HRTIMER_H |
| |
| #include <linux/rbtree.h> |
| #include <linux/ktime.h> |
| #include <linux/init.h> |
| #include <linux/list.h> |
| #include <linux/wait.h> |
| |
| struct hrtimer_clock_base; |
| struct hrtimer_cpu_base; |
| |
| /* |
| * Mode arguments of xxx_hrtimer functions: |
| */ |
| enum hrtimer_mode { |
| HRTIMER_MODE_ABS, /* Time value is absolute */ |
| HRTIMER_MODE_REL, /* Time value is relative to now */ |
| }; |
| |
| /* |
| * Return values for the callback function |
| */ |
| enum hrtimer_restart { |
| HRTIMER_NORESTART, /* Timer is not restarted */ |
| HRTIMER_RESTART, /* Timer must be restarted */ |
| }; |
| |
| /* |
| * hrtimer callback modes: |
| * |
| * HRTIMER_CB_SOFTIRQ: Callback must run in softirq context |
| * HRTIMER_CB_IRQSAFE: Callback may run in hardirq context |
| * HRTIMER_CB_IRQSAFE_NO_RESTART: Callback may run in hardirq context and |
| * does not restart the timer |
| * HRTIMER_CB_IRQSAFE_NO_SOFTIRQ: Callback must run in softirq context |
| * Special mode for tick emultation |
| */ |
| enum hrtimer_cb_mode { |
| HRTIMER_CB_SOFTIRQ, |
| HRTIMER_CB_IRQSAFE, |
| HRTIMER_CB_IRQSAFE_NO_RESTART, |
| HRTIMER_CB_IRQSAFE_NO_SOFTIRQ, |
| }; |
| |
| /* |
| * Values to track state of the timer |
| * |
| * Possible states: |
| * |
| * 0x00 inactive |
| * 0x01 enqueued into rbtree |
| * 0x02 callback function running |
| * 0x04 callback pending (high resolution mode) |
| * |
| * Special case: |
| * 0x03 callback function running and enqueued |
| * (was requeued on another CPU) |
| * The "callback function running and enqueued" status is only possible on |
| * SMP. It happens for example when a posix timer expired and the callback |
| * queued a signal. Between dropping the lock which protects the posix timer |
| * and reacquiring the base lock of the hrtimer, another CPU can deliver the |
| * signal and rearm the timer. We have to preserve the callback running state, |
| * as otherwise the timer could be removed before the softirq code finishes the |
| * the handling of the timer. |
| * |
| * The HRTIMER_STATE_ENQUEUE bit is always or'ed to the current state to |
| * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario. |
| * |
| * All state transitions are protected by cpu_base->lock. |
| */ |
| #define HRTIMER_STATE_INACTIVE 0x00 |
| #define HRTIMER_STATE_ENQUEUED 0x01 |
| #define HRTIMER_STATE_CALLBACK 0x02 |
| #define HRTIMER_STATE_PENDING 0x04 |
| |
| /** |
| * struct hrtimer - the basic hrtimer structure |
| * @node: red black tree node for time ordered insertion |
| * @expires: the absolute expiry time in the hrtimers internal |
| * representation. The time is related to the clock on |
| * which the timer is based. |
| * @function: timer expiry callback function |
| * @base: pointer to the timer base (per cpu and per clock) |
| * @state: state information (See bit values above) |
| * @cb_mode: high resolution timer feature to select the callback execution |
| * mode |
| * @cb_entry: list head to enqueue an expired timer into the callback list |
| * @start_site: timer statistics field to store the site where the timer |
| * was started |
| * @start_comm: timer statistics field to store the name of the process which |
| * started the timer |
| * @start_pid: timer statistics field to store the pid of the task which |
| * started the timer |
| * |
| * The hrtimer structure must be initialized by hrtimer_init() |
| */ |
| struct hrtimer { |
| struct rb_node node; |
| ktime_t expires; |
| enum hrtimer_restart (*function)(struct hrtimer *); |
| struct hrtimer_clock_base *base; |
| unsigned long state; |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| enum hrtimer_cb_mode cb_mode; |
| struct list_head cb_entry; |
| #endif |
| }; |
| |
| /** |
| * struct hrtimer_sleeper - simple sleeper structure |
| * @timer: embedded timer structure |
| * @task: task to wake up |
| * |
| * task is set to NULL, when the timer expires. |
| */ |
| struct hrtimer_sleeper { |
| struct hrtimer timer; |
| struct task_struct *task; |
| }; |
| |
| /** |
| * struct hrtimer_base - the timer base for a specific clock |
| * @index: clock type index for per_cpu support when moving a |
| * timer to a base on another cpu. |
| * @active: red black tree root node for the active timers |
| * @first: pointer to the timer node which expires first |
| * @resolution: the resolution of the clock, in nanoseconds |
| * @get_time: function to retrieve the current time of the clock |
| * @get_softirq_time: function to retrieve the current time from the softirq |
| * @softirq_time: the time when running the hrtimer queue in the softirq |
| * @cb_pending: list of timers where the callback is pending |
| * @offset: offset of this clock to the monotonic base |
| * @reprogram: function to reprogram the timer event |
| */ |
| struct hrtimer_clock_base { |
| struct hrtimer_cpu_base *cpu_base; |
| clockid_t index; |
| struct rb_root active; |
| struct rb_node *first; |
| ktime_t resolution; |
| ktime_t (*get_time)(void); |
| ktime_t (*get_softirq_time)(void); |
| ktime_t softirq_time; |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| ktime_t offset; |
| int (*reprogram)(struct hrtimer *t, |
| struct hrtimer_clock_base *b, |
| ktime_t n); |
| #endif |
| }; |
| |
| #define HRTIMER_MAX_CLOCK_BASES 2 |
| |
| /* |
| * struct hrtimer_cpu_base - the per cpu clock bases |
| * @lock: lock protecting the base and associated clock bases |
| * and timers |
| * @lock_key: the lock_class_key for use with lockdep |
| * @clock_base: array of clock bases for this cpu |
| * @curr_timer: the timer which is executing a callback right now |
| * @expires_next: absolute time of the next event which was scheduled |
| * via clock_set_next_event() |
| * @hres_active: State of high resolution mode |
| * @check_clocks: Indictator, when set evaluate time source and clock |
| * event devices whether high resolution mode can be |
| * activated. |
| * @cb_pending: Expired timers are moved from the rbtree to this |
| * list in the timer interrupt. The list is processed |
| * in the softirq. |
| * @nr_events: Total number of timer interrupt events |
| */ |
| struct hrtimer_cpu_base { |
| spinlock_t lock; |
| struct lock_class_key lock_key; |
| struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| ktime_t expires_next; |
| int hres_active; |
| struct list_head cb_pending; |
| unsigned long nr_events; |
| #endif |
| }; |
| |
| #ifdef CONFIG_HIGH_RES_TIMERS |
| struct clock_event_device; |
| |
| extern void clock_was_set(void); |
| extern void hrtimer_interrupt(struct clock_event_device *dev); |
| |
| /* |
| * In high resolution mode the time reference must be read accurate |
| */ |
| static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) |
| { |
| return timer->base->get_time(); |
| } |
| |
| /* |
| * The resolution of the clocks. The resolution value is returned in |
| * the clock_getres() system call to give application programmers an |
| * idea of the (in)accuracy of timers. Timer values are rounded up to |
| * this resolution values. |
| */ |
| # define KTIME_HIGH_RES (ktime_t) { .tv64 = 1 } |
| # define KTIME_MONOTONIC_RES KTIME_HIGH_RES |
| |
| #else |
| |
| # define KTIME_MONOTONIC_RES KTIME_LOW_RES |
| |
| /* |
| * clock_was_set() is a NOP for non- high-resolution systems. The |
| * time-sorted order guarantees that a timer does not expire early and |
| * is expired in the next softirq when the clock was advanced. |
| */ |
| static inline void clock_was_set(void) { } |
| |
| /* |
| * In non high resolution mode the time reference is taken from |
| * the base softirq time variable. |
| */ |
| static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) |
| { |
| return timer->base->softirq_time; |
| } |
| |
| #endif |
| |
| extern ktime_t ktime_get(void); |
| extern ktime_t ktime_get_real(void); |
| |
| /* Exported timer functions: */ |
| |
| /* Initialize timers: */ |
| extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock, |
| enum hrtimer_mode mode); |
| |
| /* Basic timer operations: */ |
| extern int hrtimer_start(struct hrtimer *timer, ktime_t tim, |
| const enum hrtimer_mode mode); |
| extern int hrtimer_cancel(struct hrtimer *timer); |
| extern int hrtimer_try_to_cancel(struct hrtimer *timer); |
| |
| static inline int hrtimer_restart(struct hrtimer *timer) |
| { |
| return hrtimer_start(timer, timer->expires, HRTIMER_MODE_ABS); |
| } |
| |
| /* Query timers: */ |
| extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer); |
| extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp); |
| |
| extern ktime_t hrtimer_get_next_event(void); |
| |
| /* |
| * A timer is active, when it is enqueued into the rbtree or the callback |
| * function is running. |
| */ |
| static inline int hrtimer_active(const struct hrtimer *timer) |
| { |
| return timer->state != HRTIMER_STATE_INACTIVE; |
| } |
| |
| /* |
| * Helper function to check, whether the timer is on one of the queues |
| */ |
| static inline int hrtimer_is_queued(struct hrtimer *timer) |
| { |
| return timer->state & |
| (HRTIMER_STATE_ENQUEUED | HRTIMER_STATE_PENDING); |
| } |
| |
| /* Forward a hrtimer so it expires after now: */ |
| extern unsigned long |
| hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); |
| |
| /* Precise sleep: */ |
| extern long hrtimer_nanosleep(struct timespec *rqtp, |
| struct timespec __user *rmtp, |
| const enum hrtimer_mode mode, |
| const clockid_t clockid); |
| extern long hrtimer_nanosleep_restart(struct restart_block *restart_block); |
| |
| extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl, |
| struct task_struct *tsk); |
| |
| /* Soft interrupt function to run the hrtimer queues: */ |
| extern void hrtimer_run_queues(void); |
| |
| /* Bootup initialization: */ |
| extern void __init hrtimers_init(void); |
| |
| #if BITS_PER_LONG < 64 |
| extern unsigned long ktime_divns(const ktime_t kt, s64 div); |
| #else /* BITS_PER_LONG < 64 */ |
| # define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div)) |
| #endif |
| |
| #endif |